Marine alien species in Italy: a contribution to the implementation of descriptor D2 of the Marine Strategy Framework Directive
SERVELLO, G.; ANDALORO, F.; AZZURRO, E.; CASTRIOTA, L.; CATRA, M.; CHIARORE, A.; CROCETTA, F.; D'ALESSANDRO, M.; DENITTO, F.; FROGLIA, C.; GRAVILI, C.; LANGER, M.R.; LO BRUTTO, S.; MASTROTOTARO, F.; PETROCELLI, A.; PIPITONE, C.; PIRAINO, S.; RELINI, G.; SERIO, D.; XENTIDIS, N.J,; ZENETOS, A.;
A re-examination of marine alien species or Non Indigenous Species (NIS) reported in Italian Seas, until December 2018, is
provided, focusing on establishment success, year of first record, origin, potential invasiveness, and likely pathways, in particular.
Furthermore, their distribution is assessed according to the marine subregions outlined by the European Union (EU) Marine Strategy
Framework Directive: Adriatic Sea (ADRIA), Ionian Sea and Central Mediterranean Sea (CMED), and Western Mediterranean
Sea (WMED). In Italy, 265 NIS have been detected with the highest number of species being recorded in the CMED (154 species)
and the WMED (151 species) subregions, followed by the ADRIA (143) subregion. Most of these species were recorded in more
than one subregion. One hundred and eighty (180 or 68%) NIS have established stable populations in Italian Seas among which
26 have exhibited invasive traits.
As regards the taxa involved, Macrophyta rank first with 65 taxa. Fifty-five of them are established in at least one subregion,
mostly in the ADRIA and the CMED. Crustacea rank second with 48 taxa, followed by Polychaeta with 43 taxa, Mollusca with 29
taxa, and Fishes with 28 taxa, which were mainly reported from the CMED. In the period 2012-2017, 44 new alien species were
recorded, resulting in approximately one new entry every two months. Approximately half of the NIS (~52%) recorded in Italy
have most likely arrived through the transport-stowaway pathway related to shipping traffic (~28% as biofoulers, ~22% in ballast
waters, and ~2% as hitchhikers). The second most common pathway is the unaided movement with currents (~19%), followed
by the transport-contaminant on farmed shellfishes pathway (~18%). “Unaided” is the most common pathway for alien Fishes,
especially in the CMED; escapes from confinement account for ~3% and release in nature for ~2%. The present NIS distribution
hotspots for new introductions were defined at the first recipient area/location in Italy. In the ADRIA, the hotspot, Venice, accounts
for the highest number of alien taxa introduced in Italy, with 50 newly recorded taxa. In the CMED subregion, the hotspots of
introduction are the Taranto and Catania Gulfs, hosting 21 first records each. The Strait of Sicily represents a crossroad between
alien taxa from the Atlantic Ocean and the Indo-Pacific area. In the WMED, bioinvasion hotspots include the Gulfs of Naples,
Genoa and Livorno.
This review can serve as an updated baseline for future coordination and harmonization of monitoring initiatives under international,
EU and regional policies, for the compilation of new data from established monitoring programs, and for rapid assessment
surveys.
2019 - Articolo in rivista
Mediterranean Marine Science (Online) 20 (2019): 1–48. doi:10.12681/mms.18711
Keywords: marine alien species, trends, MSFD, Italy, Mediterranean Sea